After he was penalized for his end-zone hit on Rams wide receiver Chris Givenson Thursday, 49ers safety Donte Whitnerwas told by a St. Louis player after the game that the shot was within the rules.

That player: Chris Givens.

"He came over when I was doing an interview and said, 'Good hit,' " Whitner said. "He thought it was legal. If the guy that was hit said it was legal - or thought it was legal - then I don't know what else to do."

Unfortunately for Whitner, the NFL doesn't share Givens' viewpoint. The league fined Whitner $21,000 on Tuesday after he was flagged for unnecessary roughness for his shoulder-to-helmet blow in San Francisco's 35-11 win. Whitner said he would appeal "immediately."

"In my heart, I felt it was legal," he said. "And I can't change the way I play."

Whitner clearly hit Givens - who was a "defenseless receiver" - in the helmet, but he has argued that it's difficult for defenders to hit a moving target in the correct spot. On Thursday, Whitner drilled Givens as the wideout was in midair and coming down with the ball. Whitner's hit broke up what would have been a 12-yard touchdown catch.

"They're all making that call based on the way the hit looked," Whitner said. "Not based on a guy actually going in there and lowering his head and using the crown of his helmet."

In Week 3, Whitner was assessed an unsportsmanlike-conduct penalty for hitting Indianapolis running back Ahmad Bradshawwith the crown of his helmet, but replays showed Whitner hit Bradshaw with his shoulder. The NFL later said it was a legal hit and Whitner was not fined.

He was hopeful his latest penalized hit would result in the same outcome.

"I know the intent is not there," he said. "If the intent isn't there, then I don't know what we can do as players. Maybe we should just put flags on and pull those off. Maybe fans will like that. Maybe not."

Staley OK: Left tackle Joe Staleysaid his left ankle is fine after he appeared to sustain a serious leg injury late in the fourth quarter of the win in St. Louis. To demonstrate his ankle's stability, he began performing one-legged hops in the locker room.

Staley is still sheepish about the high-decibel screams he produced when he was outstretched on the field with concerned teammates huddled around him.

"My mom heard it," Staley said. "She wasn't even watching the game. She heard it through a different station."